Hammer mechanism



Patented June 27, 1944 UNITED STATES PATENT OFFICE HAMIMER MECHANISM John C. Garand, Springfield, Mass. Applieation'August 21, 1943, Serial No. 499,443

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) '9 cnims;

The invention described herein may be manu- Iactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to a hammer mechanism for a firearm.

Ithas long been. appreciated in the firearm of the bolt.

Hammer designs heretofore known in the art resulted in a compromise between the foregoing desirable and undesirable features and resulted in a rebounding type hammer where the hammer spring is permitted to exert a substantial force on the hammer until the hammer reaches a'position slightly short of its position of impact with the firing pin. In this positionthe spring force is arrested and the velocity already imparted to the hammer is suflicient to produce an impact blow on the firing pin with the necessary amount of energy. In such constructions the hammer can then rebound after striking the firing pin to the point where it again is in contact with the hammer spring. This type of design thus produces a hammer which has no biasing force exerted on it in its position immediately adjacent to the firing pin. As will be recognized by those skilled in the art this condition is also undesirable since a light bias, on the order of several pounds, should be maintained on the firing pin during the discharge of the cartridge in order to prevent the primer of the cartridge from blowing out. This also results in the recoiling bolt striking the hammer an impact blow with resultant decrease in life or the parts.

Accordingly, it is an object of this invention to provide an improved hammer mechanism.

*It is a particular object of this invention to provide a hammer mechanism wherein a large spring force is exerted on the hammer until it reaches the position immediately adjacent the firing'pin and thereafter a light spring bias is exerted on the hammer.

j The specific nature of this invention as well 55 as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawing in which:

Fig. 1 is an enlarged detail view of the hammer and trigger mechanism partly in section showing the hammer in the forward or released position.

v Fig. 2 is a side elevational view of the hammer plunger.

Fig. 3 is a top elevational view of Fig. 2 partly broken away to show the auxiliary hammer spring and plunger.

Fig. 4 is an enlarged right end view of Fig. 2.

Referring to Fig. 1, there is shown one modification of this improved hammer design wherein the hammer and trigger elements are mounted on a triggerframe i. The trigger frame I comprises a base portion 2, a front upstanding portion 3, a rear upstanding portion 4, and a side wall 5. A trigger 6 is pivotally mounted on a transverse pin 1 which is supported in suitable holes in the rear upstanding portion 4 and side wall 5 of the trigger frame I. The trigger 6 comprises a lower portion 8 conventionally shaped for engagement by the finger of the operator and an upper sear portion 9 having transversely projecting locking lugs H]. A hammer l I has its one end pivotally mounted on a pin l2 which is journaled in the front upstanding portion 3 of the trigger frame I. The hammer l I has a head portion [3 suitably shaped to engage a firing pin (not shown) and a rearward bifurcated sear engaging extension I 4 provided with looking shoulders Ma. When the hammer H is pivoted to the rear, or to the left, as viewed in Fig. l, as it would be by a bolt of a firearm riding back over it in the conventional manner, the locking extensions I0 of the sear portion 9 of trigger 6 engages the locking shoulders I do of the sear engaging extension I 4 of the hammer and hold the hammer in a cooked position.

A hammer spring I5 is mounted to operate between the hammer and the trigger 6. The hammer spring [5 is partially enclosed in a spring housing I6, which housing terminates in a pair of bifurcated lugs [1. A transverse hole I8 is provided through the pair of bifurcated lugs I! by means of which the housing I6 is mounted on the pin 1. I! surround the central portion of the trigger 6. It should be mentioned that the hole 18 through the bifurcated lugs I1 is substantially larger than the diameter of the pin 1 thereby permitting a cam portion IS on the front of the In this position the bifurcated lugs the larger plunger 20. I r lft'vvill therefore be; apparent thatj'this invencentral portion of the trigger 6 to' engage that portion of the housing l6 lying between the legs is supplied to oppose pulling of the trigger. The hammer spring l surrounds a plunger m'er l I. 2| of the plunger 20 rides in a slot provided in the side wall 5. This slot stops the movespring I5 when the hammer H reaches a point pin (not shown) front surface 26 with upstanding portion: 3-" of the trigger frame I. It would therefor be-apparent that so far as the hammer spring. l5" -is concerned, there is a limited range, ofpivotal movement of the hammer in the region adjacent to its position of impact to the firing pin" whereno bias is exerted'on the hammer by the-hammer of the bifurcated lug l1 and receive the forcei exerted by the hammer spring I5. Thus a force 'thru all but one extreme portion of said hammers pivotal movement anda recess in .the end of said I plunger engaging the hammer. an auxiliary plunger mounted in said recess and an auxiliary spring mounted behind said auxiliary plunger,

said auxiliary spring biasing said. auxiliary plunger against said harmner in all positions of said hammer. v v 4. In a firearm having a firing pin, a pivoted hammer arranged to strike the firing pin and a spring biased plunger for operating the hammer, ment of the plunger 20 under the force of the the improvement comprising means for stopping 1 the movement of said plungerat a point prior to the point of impact of the hammer on the firing I pin, an auxiliary plunger movably mounted in the head of said first mentioned plunger and a spring. biasing said auxiliary plunger into engagespring. Thus the hammer will yield the desirable characteristics of the rebounding type.

"To providea light bias on the hammer in this position, a recessfl is 'provided in the head-end- In this recess an auxiliaryof the plunger 20. v spring'28 and an auxiliary plunger 29 is mounted.

,Plunger 29 has a head end shaped to engage theanotch23 of thehammer ll. Thus a light biasing force is exerted on the hammer: by aux iliary plunger 29 after the hammer reaches the end 'of slot Min-sidewall 5 ,andpasses the position where thetransverse extensionfle ofthe plunger 20 prevents the hammerspring-le "from acting further on'the hammer as illustrated in Figfl. The spring-28 is much lighter than ham: mer spring l5 hence during the cockingjmovement ofthe'hannner, thei'end 3B of auxiliary plunger 29 is flush with'the head portion 2| of plunger 26, permitting the load to be carried by tionprovides a rebounding'typeham'mer wherein a spring force of substantial ma nitudeiiscontinuously exerted on the hammer upjto the. position just short'of its .positionof impactto the firing'pin. From. that position to the'gpoint of impact ofthe'fi ring pin only alight bias, is ex cartridge. 1

I claim; i 1. In combination, a. pivoted h'ammer. movable thru a limited are, aspring biased plunger. en-Q gaging said hammer'and exerting a force thereonthru all but one extreme portion ofzsaidihammers. pivotal movement-and an auxiliaryflspringbiasedplunger operating between: saidQham mer and.

said plunger irrespective oftheilposition. ofsaid hammer. i

. In combinationj a pivotedv hammerimovable thru a limited arc, a, spring. biased plunger engaging said hammer an'djexerting ai forcelthereon thru all' but one extreme .p'ortion pf-said. hammers pivotal movement and" an auxi1iary .spi:ing.biased plunger mounted in.saidjfiifs'tmen ion'e'd plunger, said auxiliary plunger engaging saidhammenand1 exerting a force thereoncontinuously,irrespective of the position of said'harnmer.

.3. m combinationga'pivotejdiharnmer movable} thru a limited l are a spring biasedip un eri en' gaging said hammer and exerting a force thereon mer irrespective of theposition of said hammer.

ment with'said hammer whereby a bias i-sexerted on-said hammer by said auxiliary plunger in all positions of said hammer. V

I 5. A hammer mechanism comprising a frame,

a hamrner pivotally mounted onsaid frame for movementfthruia limited arc, a spring housingpivotally mounted in said 'frame, a hammer springmounted in said spring housing, a plunger biased by said spring into engagement with said hammer, means on said' frame'cooperating with said plunger to limit the movement ofsaid" plunger so that said plunger does not engage. said hammer during'the extreme portion 'ofsaid hammers pivotal -movement and resilient meansmounted between said plunger and said hammerf said resilient means exerting a-b-ias on said ham-'- 6; A hammermechanism comprising afra'me,

a hammer pivotally -mounted on" said frame for" movementthru' a limited arc, a-s'pring housing pivotally mounted 'in said frame, a hammerrfl spring mounted in said spring housing,.a'pluriger" biased by said spring intoengagement Withisaid hammer." means on said frame cooperatingfwith said plunger to limit :the 'movement of said plunger so thatsaid plunger": does not engage said hammer-during the extreme portion of said hammers pivotal movement} a spring biased auxiliary-plunger "mountedini said first mentioned'plunger, said auxiliary plunger engaging said- ;hammer' and exerting a .force thereon continuously; irrespective of the position of said" hammer.

'7. Ahammer mechanis'mfcomprisin'g1aflframe, a hammer pivotally mounted on said" frame .for' movement thruia 'limitejd' are; as'pring housing; pivotally; "mounted on said frame, a, hammer spring mounted in said spring housing; a plunger biased'bysaidspring into engagement with said] hammer, said frame having; a. slot. adjacent the I said plunger, a transverse, projection on Jsaidl plunger engaging in said slotlisaid slot. limiting. the movement of said. plunger sothat said plungerlgdoes' not engage said hammer during; the. extreme'portio'n of. saidThammers pivotalmovement and resilient lmeansl mounted between. saidj plunger and said hammemsaid resilient means exerting a bias on said hammerir:

respective of the positionof said; hammer.

- 8. Ahammer.mechanismcomprising a frame a hammenpivotally1mounted..on,said frame for a I movementfthru a limited;arc a spring housing;

piyotally j mounted, 'oh'jsai'd; name, a, hammer spring; mounted, ..in-' said; spring T. ho'usingi. .Yaj into engagement plunger biased bysaid ism A with 'sa'id'h'amm'er, said frame ,having..al..sllotiad .jacent the said. plunger, aransverse prtjetnon' onsaid plunger engaging in said slot," said slot limiting the movement of said plunger 50 that said plunger does not engage said hammer during the extreme portion of said hammers pivotal movement, a spring biased auxiliary plunger mounted in said first mentioned plunger, said auxiliary plunger engaging said hammer and exerting a force thereon continuously, irrespective of the position of said hammer.

9. A hammer mechanism comprising a frame, a hammer pivotally mounted on said frame for movement thru a limited arc, a spring housing pivotally mounted on said frame, a hammer spring mounted in said spring housing, a plunger biased by said spring into engagement with said hammer, said frame having a slot adjacent the said plunger, a transverse projection on said plunger engaging in said slot, said slot limiting the movement of said plunger so that said plunger does not engage said hammer during the extreme portion of said hammers pivotal movement, a recess in the end of said plunger engaging the hammer, an auxiliary plunger mounted in said recess and an auxiliary spring 10 mounted behind said auxiliary plunger, said auxiliary spring biasing said auxiliary plunger against said hammer in all positions of said hammer.

JOIDI C. GARAND. 

